Devices serving as connectors for flexible tubing have been heretofore provided and described in patent literature. Previously disclosed connectors usually effect a firm fit by making use of a connecting portion of generally conical shape, with or without stepped flanges of increasing diameter, which connecting portion is inserted longitudinally into the tubing bore for a given distance which results in sufficient stretching of the tube's circumference causing a snug grip on the outer periphery of the connector by the tube's internal surface.
Desaultels in U.S. Pat. No. 3,100,490, issued Aug. 13, 1963, disclosed a surgical drainage tube which employed a catheter adapter with a smooth tapered tip that flared outwardly as the distance from the end of the tip increased.
Strawn in U.S. Pat. No. 3,307,552, issued Mar. 7, 1967, discloses catheter tubing plugs employing conically shaped plug means which functionally engage the internal walls of the catheter tubing when pressed into the tube's longitudinal bore. This frictional engagement may be increased, according to Strawn, by providing a plurality of stepped frictional elements or spaced ring memnbers.
Hodge in U.S. Pat. No. 3,767,233, granted Oct. 23, 1973, discloses a coupling device for joining flexible tubing. This connector unit is of generally semi-cylindrical contour tapering from midsection to a lesser dimension at the ends, the outer surfaces of the tapered portions being provided with a plurality of projections to form surface irregularities for gripping the inner tubing surfaces. These surface irregularities are described by Hodge as suitably being a series of frustoconical sections of progressively increasing size from the ends toward the midsection.
Both Dye, et al., U.S. Pat. No. 3,830,241, issued Aug. 20, 1974 for a vented adapter and Yum, et al., U.S. Pat. No. 3,831,600, issued Aug. 27, 1974 for a variable fluid flow control, utilize tubing connectors with stepped surface irregularities.
The following patents disclose connectors utilizing tapered sleeves for engaging flexible tubing.
Barton, U.S. Pat. No. 3,990,597, issued Nov. 9, 1976 for a container and gavage tube adapter with vent.
Tenczar, U.S. Pat. No. 4,022,205, issued May 10, 1977 for fluid connectors.
Hanson, et al., U.S. Pat. No. 4,261,339, issued Apr. 14, 1981 for a balloon catheter with rotatable support.
Burd, U.S. Pat. No. 4,133,312, issued Jan. 9, 1979 for a connector for attachment of blood tubing to external arteriovenous shunts and fistulas.
The Burd patent discloses a universal connector for a blood tubing set employing a sleeve-like tip which relies on both its external and internal taper for a wide range of tubing adaptability. Additionally, a locking means is disclosed for prevention of accidental disengagement of the tubing. This has been a common problem especially for connectors which are designed to fit a broad range of tubing sizes.
Equally troublesome, especialy in clinical situations, is the reverse problem: ease of disconnection.
Spiegel in U.S. Pat. No. 3,731,648, granted May 8, 1973, described a hinged connector interposed between the catheter and an inlet-outlet tube in an irrigation and urinary drainage apparatus which could be closed or opened without disconnection of any elements of the system. This connector couples the cathether by means of an insertable tip with an exterior shell of frusto-conical configuration having a series of ribs disposed abut its circumference. The advantage of uncoupling a hinged connector to open the system is described in the patent specification as avoiding the difficulties in removing the semirigid tip from the flexible rubber catheter tubing which " . . . requires use of a pulling and twisting motion and separation is often so abrupt and violent that . . . there is a danger of accidentally pulling on the catheter itself and causing discomfort or even trauma to the patient . . . ."
There are, however, applications in which disconnection is required as for attachment of a new supply container for example when tube feeding patients. One objective then, of the present invention, was to make a connector that provided a secure leak-proof fit but that was also easy to disconnect. A second objective was to make an adaptable connector that could provide this type of fit to a wide variation in tubing sizes ranging from very small tubes used in nasogastric intubation of infants to large gastrostomy tubes placed in adults. The connector of the instant invention realizes these objectives by virtue of construction of its adaptable tip, which differs from connectors previously disclosed by incorporating a smooth tapered surface near the tip end for connecting with smaller tubing and further from the tip end, a surface with stepped frictional rings for connecting with larger tubing.